European patent Nos. 181790 and 183579, in the Applicant's name, disclose a oxy-iodination of benzene, mono-iodo-benzene and small amounts of di-iodo-benzene being thus formed; whilst the mono-iodo derivative can be advantageously used on an industrial scale, e.g., for the manufacture of phenol, the di-iodo-benzenes have not yet found a sufficiently wide application field.
The Applicant has surprisingly found that particular and suitable operative conditions allow the di-iodo-benzenes to be easily trans-halogenated into mono-iodo-benzene, in the presence of oxygen and of benzene, according to the reaction: ##STR1##